x402-gated product inventory endpoint on Base, pay-per-call with USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a product inventory resource (product ID 51) via the x402 payment protocol. The endpoint is live and returns a 402 challenge requiring payment in USDC on the Base network. The price per request is $0.02 (20,000 base units of USDC with 6 decimals). Payment is made via the x402 "exact" scheme, meaning each call requires a one-time micropayment with no API keys, subscriptions, or rate limits.
The hosting site lowpaymentfee.com offers a broad catalog of x402-gated APIs spanning data & analytics, AI/ML inference, finance & Web3 data, and infrastructure utilities — all priced at $0.02 per request. This specific endpoint (/api/v1/products/51/inventory) is listed under "Premium API Access" but its exact response payload is undocumented; no OpenAPI schema, example responses, or detailed documentation were found in the crawl. The docs, pricing, API, and README pages all returned only a "Connect wallet" prompt with no substantive content.
The endpoint accepts POST requests and settles payments to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 using USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) on Base. The maximum timeout for payment settlement is 300 seconds. Because the response schema and request body format are not documented, callers will need to experiment or contact the provider to understand the expected input and output structures.
Capabilities
Use cases
- —Querying product inventory data with per-request USDC micropayments
- —Integrating inventory checks into autonomous agent workflows without API key management
- —Building pay-as-you-go commerce data pipelines on Base
Fit
Best for
- —Agents or apps that need keyless, pay-per-call access to inventory data
- —Developers experimenting with x402 payment protocol integrations
- —Use cases where avoiding subscription commitments is important
Not for
- —Production systems requiring well-documented request/response schemas
- —High-volume inventory queries where per-call pricing may add up
- —Users who need fiat-only payment options
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/products/51/inventory
# Returns 402 with x402 challenge; attach X-PAYMENT header with USDC payment proof on Base to access.Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge, but there is no documentation, no OpenAPI schema, no example requests or responses, and the docs pages are empty stubs. The purpose of 'product inventory for product 51' is vague and unexplained.
Warnings
- —No API documentation available — docs, pricing, API, and README pages all show only 'Connect wallet' with no content.
- —No request body schema or response schema documented; callers must guess the expected input format.
- —The specific purpose and data returned by /api/v1/products/51/inventory is unclear — 'Premium API Access' is a generic label.
- —This endpoint is not listed on the provider's homepage catalog, raising questions about its status.
Citations
- —The endpoint returns a 402 challenge with x402Version 1, requiring USDC payment on Base networkhttps://lowpaymentfee.com/api/v1/products/51/inventory
- —maxAmountRequired is 20000 base units of USDC (USD Coin, 6 decimals) = $0.02https://lowpaymentfee.com/api/v1/products/51/inventory
- —The site advertises $0.02/request pricing with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —Payment is sent to 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 using USDC contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/products/51/inventory
- —Docs, pricing, API, and README pages returned only 'Connect wallet' with no substantive documentationhttps://lowpaymentfee.com/docs